EZ Vise. Easy to print, easy to use, easy to slide and snap into dimensions before tightening. I tested printing this with both PETG anda PLA+. Apply lube like silicon grease to screw before tightening. First time around it will be harder but consequent turns will be easier.
See my Instagram video for assembly and usage.
Only rail needs to be printed 2x. Screw and rails both should be printed horizontally laid down on their flat cut surface. Jaws linear slot should be facing upwards.
PS: All threads are left handed. Turning handle clockwise tightens it. During initial assembly you won't have the handle yet, you can use the nut side and turn it counter-clockwise to tighten it.